Electric-arc lamp



Patented May l, 1883.

Mw www 'Lee YS t WW2 Nm OM@ Wwf UNTTED STATES PATENT OFFICE.

LEO DAFT, OF GREENVILLE, NEW JERSEY.

ELECTRIC-ARC LAMP.

SPECIFICATION forming part of Letters Patent No. 276,567, dated May 1, 1883.

Application filed February 13, 1882.

To all whom it may concern:

Beit known that I, LEO DAFT, a subject of the Queen of Great Britain, residing at Greenville, in the county of Hudson and State of' New Jersey, have invented new and uset'ul Improvements in Electric Lamps, ot' which the following is a specification.

This invention consistsin combining with the axial magnet ot' an electric lamp an interior movable coil attached to the core ofthe axial magnet. This interiorcoil is placed in a shuntcircuit around the circuit passing through the coil ot the axial magnet.

The invention also consists in a new and simple arrangement of magnetic clutch, the said clutch being attached to the core ot' the axial magnet, and being iniluenced by the varying magnetism ot" said core.

`rlhis invention is illustrated in the accompanying drawing, which represents a vertical section. v

In this drawing, the letter A designates an axial magnet, B its soft-iron core, and C the carbon-holder, which extends loosely through the core, and is connected to the same by the rings a a, which embrace the carbon-holder, and each of which is connected to a lever, D. These levers are connected to an insulating frame or support, B', on the core B by pivots b, and their upper ends are made concave to correspond to the circumference of the core, and they form armatures which are attracted by the core whenever the same becomes magnetized. To the core B is firmly secured a plate, P, which rests upon springs Q for the purpose of balancing the weight of the core. 'lhe carbon-holder is guided by grooved rollers 1' i'. Aslong as the electric arc remains in its normal condition the attractive force of the core B on the armature D retains the carbonholder firmly in position; but whenever the attractive force of the core decreases, the armatures D release the carbon-holder, so that the same slides down. As soon as the proper electric arc is restored the downward movement ofthe carbon-holder is again arrested, and in this manner the electric arc is controlled antomatically. In the core B is a recess, c, and in this recess is situated the regulating-helix E. This helix is situated in a sh uut-circuit around the main helix A, and it is made oi very tine (No model.)

wire, so that the resistance is much greater than that ot' the main helix, the proportion beA ing about seventy-tive to one, so that by far thelargest portion ofthecnrrentpasses through said main helix. The regulating-helix E is wound in a recess formed in the movable coro, and is located in a shunt around the are. lt is so wound and connected that when, owing lo the abnormal resistance ofthe arc, more ot' the current flows through it than through the main helix, it will induce magnetism in the movable core B of opposite polaritv to that induced by the main helix A. The length ot' the are is regulated as follows: rlhe weight of the core being nearly balanced upon the springs Q, the tendency ot' the main helix A is to draw up the core B, and with it the upper carbon, thereby lengthening the are and increasing the resistance at that point, the effect of. which is to directaportion of thecurrentthrough the smaller helix,which,beingoi'oppositepolarity,operates by opposite induction to weaken the liftingpower ot' the main helix, so that the core will drop and the earbons will approach until the normal length ot'arc is re-established. it', l'rom any cause, more than the intended quantity ci" current iiows through the main helix A, the tendency would be to momentarily increase the length ofthe are; but as that increases the resistance more current will iiow through the opposing helix E, and as the increased niagnetism ot' the helix A in the movable iron core B is met hy a similar but opposite force from the helix E, any appreciable permanent change in the arc is prevented.

l am aware that a clutch has been heretofore provided which moves with the core ol" an axial magnet, the said clutch being adapted to be operated by magnetic repulsion instead ci' by magnetic attraction, as is shown in my lamp. It is found in practice impossible to operate by magnetic repulsion, because when the core is very magnetic, instead of repelling the clamp, it will attract it, just as a greater magnet will attract a lesser magnet,whichever pole of the lesser magnet be presented to the more power- IOO tric lamp, of a helix in the main circuit, provided with a sliding core, a differential helix in a shunt around the arc, wound upon said core, and regulating mechanism for the carbons, connected to and actuated by said helices and core, what l claim as new, and desire to secure by Letters Patent, is-

1. The c0mbination,iu an electric lamp or regulator, of an axial magnet, its movable core, a secondary helix attached to and moving with said core, and a magnetic clamp attached to said core, but magnetically insulated from the same, the said clamp seizing the carbon-holder when attracted by the varying magnetism ot' the core, said magnetism being occasioned by the resultant of the magnetism induced by the external and the secondary oeils, substantially as described.

2. An electric lamp provided with an outer main helix, a central movable core carrying a regulating-helix, a movable carbon-holder, and a clutch consisting of pivoted armature levers and rings controlled and regulated by the varying magnetism of the core, as shown and de scribed.

3. The combination, in an electric regulator, ot' a principal coil with a hollow interior secondary or differential helix, which rises and falls by the Varying magnetism of the main coil, and a carbon-holder centrallylocated with rcferenceto the main and differential coils and passing through said differential coil, substantially as described.

ln testimony whereof I have hereunto set my hand and seal in the presence ot' two subscribing witnesses.

LE() DAFT. |`L. SII Titnessesz W HAUFF, OTTO HUFELAND. 

